Concealed hook latch



. April 27, 1954 R, w. oss 2,676,825

CONCEALEID HOOK LATCH Filed Dec. 5, 1950 r 2 sheets-shank 1 I INVENTOR.RAYMOND W. ROSS BY I ATTORNEYS April 27, 1954 R. w. RYOSS. 2,676,825

CONCEALED HOOK LATCH Filed Dec. 5, 1950 Fi s 2 Sheets-Sheet 2 III/I,

INVENTOR. RAYMOND W. ROSS WM a; M

ATTOR N EYS Patented Apr. 27, 1954 STATES OFFICE 2,676,825 CONCEALEDHOOK LATCH Raymo d W'. Russ, Philadelphia, Pa.,' assig to Leeds" andNorthrup company; Philadelphia, Pa.; 9; corporatidii of PennsylvaniaApplication December 5, 1950, Serial No. 1239,27"?

4' Claims. 1

This invention relates to latches for fastening relativelymovablememb'ers non, for example, as the lid and case of an instrumenthousing.

The present invention is particularly suited to housings for portableinstruments which must of necessity be moved to various sites. For suchhousings, this latch is particularly advantageous in that its appearancegives'p'ositive and immediate indication as towhether thehousing'ha's'been set in latched position oi is in unlatched' position. When themovable latching'member and handle elements of the latch occupy,relative to each other, any displacedangular position whatsoever, itwill be known that the latch has not been set in its fully latchedposition, whereas when the handle overlies, conceals and coversthe'movable latching member, it will be known that that member has beenmoved to its fully latched position. Thus, any exposure of theparts'underlying the handle will be indicative of the fact that thelatch has not been set-aridthe danger of damage caused by the instrumentfalling is avoided.

In carrying out the invention, there is provided a latch comprising apivoted structure and a latchable member, wherein the pivoted structureincludes a movable latching member such as a hook and a handle, withpins and cams associated with the hook and handle and'with the base onwhich the latch is mounted'to control the relativemovement between thehook and the handle; and with the handle overlying the hook and thelatchable member to cover the Working members of the latch when inlatched position. While the movable latching member is shown'as a hook,it will-be obvious to those skilled in the art that the cooperativerelationship between themovable latching member and the stationarylatching or latchable member can be provided by serrated or frictionallyengaging surfaces rather than by a hooked engagement. I e

For a morecomplete understanding of the invention, reference should'behad to the following description taken in conjunction with theaccompan'ying drawingsin which:

Fig. 1 is a perspective view of a box with a hook latch of applicantsinvention in unlatched position;-

Fig. 2'is a View similar to that of Fig. l with the hook latch inlatched position;

Fig. 3 is a rear view of one embodiment-of the latch structure; 7 u v IFig. 4 is asectionalview along line 4-4 of Fig. 51s a rear view of theembodiment illustratedin Fig. 3, in latched position; I 7 V Fig. 6 isa-rear view of a modi-fication of the embodimentillustratedin Figt 3Fig. 7 is a rear view oftheg. 6 modification with the latch'i'nitsclosedposition; Y

Fig: 8 is a rear elevation oi anotherhenilaodi ment; with the heckandhandle iifunlatchedpositi'onj Fig. 9 is a rear elevation of the hookand handle of Fig. 8 approaching the latched position;

Fig. 10 is a rear elevation or the hook and handle of Fig. 8 in thelatched position; and

Fig. 11 is a sectional view along line l||| of Fig. 10.

It is to be noted that all of the detailed views, Figs. 3, 5, 6, 7, 8,9, and 10 are rear views, selected because of the covering feature ofhandle 3. Accordingly, it will be understood that statements of rotationin the clockwise or counterclockwise direction in descriptions of thesefigures is in the opposite sense to the description that would be givenfor the same motion when normally viewed from the front of the latch andhousing.

Referring now to a front View, Fig. l, the latch is shown attached tothe hinged lid I of an instrumentcase 2 of a type carried by a handleafiixed to the lid. The latch 4 is adapted to be swung into engagementwith a. latchable member such as shoulder screw 5 attached to case 2. Alatch handle 3 has a wide-angle, i. e., about right-angle, relationshipwith latch or hook member 4 when in the unlatched position. As willlater be described in connection with Figs. 3, 6 and 8, thisrelationship is maintained by frictionally associated and bycam-engaging structures while the hook and handle are swung clockwise.When hook 4" engages screw 5 upon counterclockwise movement of handle 3,the rotary motion of hook 6 is stopped b'ut handle 3 continues to rotateabout sha t' 6' and moves relative to hook 4 to a positio'riwhere handle3 overlies all Working parts of the hook 4 and the latchable member 5.

Fig. 2" showsthe latch in closed position wherein the latched conditionis indicated by the comp'le'tefconcealment of all latch part whichunderlie the" handle. Any motion of the handle 3 will expose someportion of the hook which underlies it, and the exposure of this hookwill serve to indicate a departure from the latched position. Further,the cavity in handle 3 receives member 5 and provides a safety-catchaction.

Fig. 3sh'ow's a rear View of one embodiment of the pivoted structureused with the structure of Figs. 1 and 2. Handle 3 is mounted on pivotshaft 6" and can be swung freely about axis of shaft 6. Cam 1 isattached to handle 3 and is a circular cam, eccentric to shaft 5 asshown. Hook 4 has'ca'm'surface an associated with cam 1. The surface 4aengages a major fraction of the circumference of can! 1. The remainingassociated surface 417 of hook 4 has a larger radius of curvature Rwhich allows clearance radially for retaining or spring member 8. Theangular length of'su-riace lib is such as to limit angular displacementof'handle 3 and'hook 4 to Accordingly, hook 4 when in the positionillustrated in Fig. 3 will resist movement relative to handle 3, sinceoverlap S frictionally engages hook 4. The resuiting" reaction resistssuch relative motion and maintains the aforesaid'wide-angle relationshipas the handle 3 moves hook 4 toward its latch-em gaging position.

Assume now a movement of handle 3 and hook i in a counterclockwisedirection, as viewed in Fig. 3, to a point where hook 4 abuts alatchable member 5. The hook 4 is thus brought to a standstill butcontinued movement of handle 3 by application of an increased forceovercomes the resistance interposed by overlap 9. The resulting relativemotion between handle 3 and hook 6 turns cam l in hook d and draws hook4 up or radially retracts it into latching engagement with member 5.Movement of handle 3 is continued until it overlies hook 4 and receivesthe latchable member 5 in a cavity provided in the handle 3 asillustrated in Fig. 5. In this final latching position, the handle 3protects, and, by covering all the working parts of the latch, serves asan indication that the latch has been fully set. It is to be furtherobserved in Fig. 5 that with hook 4 in its latched and radiallyretracted position the longitudinal axis thereof as well as that ofhandle 3 are in substantially the same plane.

When it is desired to open the latch, the handle 3 is turned clockwisefrom the position shown in Fig. 5 about the axis of shaft 6 towards theposition shown in Fig. 3. Lip ill on hook 4 prevents hook 4 fromfollowing handle 3. The relative movement between handle 3 and hook 4rotates cam i to move or extend radially hook 4 downward until lip itclears latchable member 5. The handle is then at or near the positionwhere overlap 9 of retaining member 8 abuts the shoulder forming the endof the enlarged radius of surface 41). Hook 4 then swings with handle 3to the illustrated unlatched position.

As shown in Fig. i, shaft 6 and cam 1 are rigid members attached tohandle 3. The shaft 63 extends through lid 1 and is affixed thereto byconventional means, such as spring snap washer ii engaged in a groove 12in pivot shaft 6 and abutting the inner Wall of lid i. Cam '1 spaceshandle 3 a distance away from the front of lid I greater than thethickness of hook member 4. Hook member s is mounted upon cam member Iand held close to handle 3 by member 3. With the described arrangement,Figs. 3 and 4, it can be seen that hook 4 swings about shaft 6 and cam iwithout touching the surfaces of lid l or case 2. In this mannerunsightly scratches are avoided. The embodiment of Figs. 3 and i leavessomething to be desired in that the frictional engagement betweenoverlap 9 and hook 4 does not give rise to a positive force comparableto one which may be developed by a direct drive between the parts.However, in some applications the direct drive may not be preferred. Forsuch applications, it may be desirable to utilize the arrangement ofFigs. 6 and 7 to assure movement of hook t and handle 3 to theirWide-angle relation in the event they should be forced toward theiroverlapping positions with the hook 4 free of latch member 5. When thelatter eventuality occurs, the wide-angle relationship between handle 3and hook 4 can be readily restored by a pin 28 mounted in lid I, asshown in Figs. 6 and 7, as will now be described. To restore thewide-angle relation between. handle 3 and hook t, handle 3 is rotated inthe clockwise direction until hook 4 abuts pin 28. The motion of handle3 may then be continued, but further movement of hook 4 is prevented bypin 23. When handle 3 reaches the position illustrated in Fig. 6, itsmotion is also arrested by 4 the abutment of overlap 9 against theshoulder at the end of angular surface 41). It is to be observed pin 28is located near enough to the pivotal axis to assure concealment of thesame by handle 3.

Figs. 8-11 illustrate another embodiment of the invention comprising asimple and rugged structure adapted to production processes and whichprovides the direct drive for actuating a hook 4 and for controlling itsmotion relative to the handle 3 both during latching and un latchingoperations.

In the unlatched position illustrated in Fig. 8. handle 3 and hook 4 areheld in the illustrated position by the combined action of a pin 20mounted in the handle 3, a pivot shaft 6 mounted in handle 3 and turningin lid l, and a pin 22 mounted in lid all associated with theirrespective cams 2|, 26 and 23 of hook 4. As handle 3 is rotatedcounterclockwise from the position in Fig. 8, a rotational motion ofhandle 3 and hook 4 in unison about pivot shaft 6 is the only motionallowed until pin 22 enters the shortradius turn in cam surface 23. Fig.9 shows the relative position of handle 3 and hook 4 just before pin 22enters the short-radius turn in cam surface 23. When pin 22 traversesthe shortradius turn in cam surface 23 continued motion of handle 3causes pin 2%, carried by handle 3, to act on cam suriace 2| to movehook 4 upward into latching engagement with member 5 as handle 3 ismoved relative to hook 4 into the overlying position illustrated in Fig.10. It will be noted thatin the cycle of movements from the position ofFig. 8 to that of Fig. 10, the center of rotation for hook 4 shifts frompoint 24 to point 25 as hook 4 is drawn up into latched position. Pins2!} and 22 are equidistant from shaft ii, pin 25 being mounted in handle3 and pin 22 being mounted in lid I.

It will be seen upon examination of Figs. 8, 9, and 10 that cam surface12! is a short section of are about center 25 with a short aperture atone end; while cam surface 23 is a short section of are about center 24witha short aperture at the end opposite the short aperture in camsurface 2!. In the cycle of movements from the positions shown in Fig. 8to those shown in Fig. 10, handle 3 is moved in the counterclockwisedirection and, through pin 2?! acting on cam surface 2|, forces hook 4to rotate with it. Hook 4 begins rotation about point 24 and is shiftedso that its point 25 coincides with the center of shaft 6 as hook 4 isdrawn upward into latched position by the camming action of pin 2!!moving along cam surface 2!. The counterclockwise motion of handle 3relative to hookl is stopped in the desired overlying position shown inFig. 9 by pin 20 abutting the end of cam surface 2|. In Fig. 11 the headof member ii abuts the end of the cavity in handle 3 as pin 20approaches the end of cam surface 2! thus acting as a stop to accuratelyposition the handle relative to the hook in the closed position.Similarly, hook 4 abuts member 5 and is drawn up into close latchingengagement as pin 22 approaches the end of cam surface 23. The design ofthe modification just described is such that small pins 20 and 22 arenot required to transmit large turning or camming forces and areprotected from damage.

When the latch of Figs. 8-11 is to be opened, handle 3 is turnedclockwise from the position shown in Fig. 10. The pin 20 moves along camsurface 21 until it enters the short-radius portion thereof, camminghook 4 downwardly out of engagement with member 5. The relation of pin22 in cam slot 23 is such that hook 4 is moved downwardly beforepermitting any rotation thereof. As the motion of handle 3 is continuedin the clockwise direction, pin 20 rotates hook 4, the fixedrelationship characteristic of the unlatched position shown in Fig. 8being maintained by the action of pin 22 in cam slot 23. Handle 3 andhook 4 then continue to rotate in this fixed relative position until theposition illustrated in Fig. 8 is reached. At this point pin 22 abutsthe end of cam surface 23, and both the hook and the handle are arrestedin that position.

While preferred embodiments of the lock have been shown, it will beobvious to those skilled in the art that other arrangements of cam andfriction members maybe utilized in accordance with applicant's teachingswithout departing from the scope of this invention as set forth in theappended claims.

What is claimed is:

1. A hook latch for a stationary latching member comprising a pivotshaft, a hook member car ried by said shaft and relatively rotatableabout its axis and movable transversely with respect thereto, anactuating handle having dimensions of length and breadth relative tothose of said hook member for forming a concealing cover for said hookmember when the handle is moved to a latching position with itslongitudinal axis in alignment with that of said member, said handlehaving a recess formed on an underside adjacent an end thereof forreceiving the latching member, said pivot shaft being secured to andextending outwardly and away from the underside of said handle adjacentan end portion thereof, and cam surfaces movable by said handle andhaving shapes which upon rotation of said handle from an unlatchingposition to said latching position move said hook member transversely ofthe axis of said shaft, said handle at the completion of said latchingmovement overlying and covering the length and breadth of said hookmember and disposed in covering relationship over the latching member toindicate the completion of the latching operation.

2. A hook latch for a stationary latching member comprising a pivotshaft, a hook member carried by said shaft and relatively rotatableabout its axis and movable transversely with respect thereto, anactuating handle having dimensions of length and breadth relative tothose of said hook member for forming a concealing cover for said hookmember when the handle is moved to a latching position with itslongitudinal axis in alignment with that of said member, said handlehaving a recess formed on an underside adjacent an end thereof forreceiving the stationary latching member, said pivot shaft being securedto and extending outwardly and away from the underside of said handleadjacent an end portion thereof, cam surfaces movable by said handle andhaving shapes which upon rotation of said handle from an unlatchingposition to said latching position move said hook member transversely ofthe axis of said shaft, and a spring member disposed between saidmovable hook member and said handle for developing a frictional drivetherebetween while they are in wide angled relationship, said handle atthe completion of said latching movement overlying and covering thelength and breadth of said hook member and disposed in coveringrelationship over the latching member to indicate the completion of thelatching operation.

3. In combination, a hook member adapted to be rotated and radiallyextended and retracted with respect to a stationary latching member,movable cam surfaces, and an actuating handle having dimensions oflength and breadth re1ative to those of said hook member for forming aconcealing cover for said hook member when the handle is moved to alatching position with its longitudinal axis in alignment with that ofsaid member comprising a pivot shaft secured to and extending outwardlyand away from the under surface of said handle adjacent an end portionthereof, said handle having a recess formed on the under surfaceadjacent said hook member extending from one side thereof toward butterminating short of the other side thereof and adapted to receive thestationary latching member, said cam surfaces being movable by saidhandle and having shapes which upon rotation of said handle from anunlatching position to a latching position move said hook member in adirection along its longitudinal axis for engaging the stationarymember, the rotation of said handle being limited upon completion of thelatching movement by a wall of the recess, said handle upon thecompletion of the latching movement overlying and covering the lengthand breadth of said hook member and disposed in covering relationshipover the latching member to indicate the completion of the latchingoperation.

4. A hook latch for a stationary latching member comprising a pivotshaft, a hook member carried by said shaft and relatively rotatableabout its axis and movable transversely with respect thereto, anactuating handle having dimensions of length and breadth relative tothose of said hook member for forming a concealing cover for said hookmember when the handle is moved to a latching position with itslongitudinal axis in alignment with that of said member, said pivotshaft being secured to and extending outwardly and away from theunderside of said handle adjacent an end portion thereof, a first camsurface on the underside of said handle and eccentric with said pivotshaft, a second cam surface on said hook member for engaging a majorportion of said first cam surface, said second cam surface having anoffset arcuate surface spaced from said first cam surface, and a springmember disposed between said movable hook member and said handle andpassing through the space between said offset surface and said first camsur face for developing a frictional drive between said handle and hookmember while they are in wide angle relationship, said cam surfacesmovable by said handle and having shapes which upon rotation of saidhandle from an unlatched position to said latched position move saidhook member transversely of the axis of said shaft, said handle at thecompletion of said latching movement overlying and covering the lengthand breadth of said hook member and disposed in covering relationshipover the latching member and cam surfaces to indicate the completion ofthe latching operation.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 567,620 Smith Sept. 15, 1896 685,469 Hasenpflug Oct. 29. 19011,517,995 Langenau et a1 Dec. 2, 1924 2,151,219 Madsen Mar. 21, 19392,514,980 Vincent July 11, 1950

